A scroll compressor has a low vibration and low noise characteristic. Moreover, in the scroll compressor, compressed fluid flows in one direction, so that fluid resistance becomes small in high speed operation. Therefore, the scroll compressor has high compression efficiency, and becomes widespread.
The conventional scroll compressor is formed as follows. A motor and a compressing device are placed in a hermetic shell, and the compressing device forms a plurality of compression chambers by engaging a fixed-scroll parts and a orbiting-scroll parts. In addition, refrigerant gas or the like for air conditioning is sucked and compressed by moving the compression chambers toward a center of a scroll of the orbiting-scroll parts with its volume reducing.
A tank for high pressured lube oil is disposed at the opposite side of a orbiting-scroll wrap of the orbiting-scroll parts, where the high pressured lube oil lubricates and cools a bearing or a crankshaft of the orbiting-scroll parts. Besides, a chamber where a rotation-restricting parts is disposed for preventing rotation of the orbiting-scroll parts is linked to the tank via a decompression part. The high pressured lube oil is decompressed at the decompression part and supplied to the rotation-restricting parts for lubricating. Furthermore, the lube oil is supplied from the chamber to an suction chamber of the compression chambers via a pressure-controlling device. Thus the lube oil has roles of a seal for preventing a leak of the compressed refrigerant gas or the like in the compression chambers, and lubrication of a contacting surface between a fixed wrap of the fixed-scroll parts and the orbiting-scroll wrap of the orbiting-scroll parts.
However, in the structure mentioned above, an inside diameter of a fine hole has to be smaller and a path length of the fine hole has to be longer to make decompression effect at the decompression part more effective. In that case, the fine hole tends to be closed with dust or the like, so that the characteristics of the compressor deteriorate and processing thereof becomes complicated.
Moreover, when compression ratio or an absolute value of pressure difference between high pressure and low pressure is large, a flow of the lube oil to the suction chamber increases, so that compression efficiency deteriorates.
An object of the present invention is to provide easy processing of a hole of a decompression part, and a scroll compressor which efficiently works by supplying an appropriate amount of lube oil to compression chambers.